Influence of cumulenic chains on the vibrational and electronic properties of sp-sp2 amorphous carbon
Articolo
Data di Pubblicazione:
2007
Citazione:
Influence of cumulenic chains on the vibrational and electronic properties of sp-sp2 amorphous carbon / L. Ravagnan, P. Piseri, M. Bruzzi, S. Miglio, G. Bongiorno, A. Baserga, C.S. Casari, A. Li Bassi, C. Lenardi, Y. Yamaguchi, T. Wakabayashi, C.E. Bottani, P. Milani. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 98:21(2007), pp. 216103.216103-1-216103.216103-4.
Abstract:
We report the production and characterization of a form of amorphous carbon with sp-sp2 hybridization (atomic fraction of sp hybridized species >or=20%) where the predominant sp bonding appears to be (=C=C=)n cumulene. Vibrational and electronic properties have been studied by in situ Raman spectroscopy and electrical conductivity measurements. Cumulenic chains are substantially stable in high vacuum conditions for temperatures lower than 250 K and they influence the electrical transport properties of the sp-sp2 carbon through a self-doping mechanism by pinning the Fermi level closer to one of the mobility gap edges. Upon heating above 250 K the cumulenic species decay to form graphitic nanodomains embedded in the sp2 amorphous matrix thus reducing the activation energy of the material. This is the first example of a pure carbon system where the sp hybridization influences bulk properties.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
amorphous state ; carbon ; electrical conductivity ; Raman spectra ; thin films
Elenco autori:
L. Ravagnan, P. Piseri, M. Bruzzi, S. Miglio, G. Bongiorno, A. Baserga, C.S. Casari, A. Li Bassi, C. Lenardi, Y. Yamaguchi, T. Wakabayashi, C.E. Bottani, P. Milani
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